Epoxy putty or "tootsie roll" epoxy (such as Abatron's WoodEpox) is one of the best things to come along in
a while for making repairs on moldings, architectural elements
and carvings that are missing small pieces. By simply kneading the "dough"
together and sanding or otherwise milling it after it hardens, this material can
make quick repairs of intricate shapes and details.
Also, epoxy putty will cling to most anything that is remotely porous.
After you experiment with it a little, I'm sure many other uses will come to mind.
Here are some tips for working with it:

Be sure to completely knead the two parts together creating one single color.

Dry powders can be added during the mixing process to help match the existing area being
patched. Raw umber for walnut, burnt umber for mahogany etc. Some companies
make epoxy putty in a variety of colors.

Add water/saliva to your fingers or tools when shaping to keep them from sticking to the putty.

Try to shape the putty as fast as possible to allow for "fine tuning" of the shape later.

Utilize ANY tool that will help to achieve the shape you are after. A sharpened pencil, ruler,
carving tools and so on.

After shaping it, keep your fingers out of it! (After mixing, I usually keep a little piece of the mixture off to the side just to keep track of hardness.)

After the putty becomes firm is when I get out the carving chisels, files and rasps to create the final shape.

Be sure to wait until the putty is completely hard before sanding smooth, creating grain lines and
so on.

I do not recommend epoxy putty for restoring any area that may involve structural integrity
or performance.

Although this type of putty does accept stains or dyes to some extent, after coloring I always seal the
putty with plain white or yellow glue before finishing. This way the putty will
not absorb a lot of finishing material and can be fine tuned even further for an exact match
of the surrounding area.